WO2015037509A1 - Élément coulissant et son procédé de production - Google Patents

Élément coulissant et son procédé de production Download PDF

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Publication number
WO2015037509A1
WO2015037509A1 PCT/JP2014/073317 JP2014073317W WO2015037509A1 WO 2015037509 A1 WO2015037509 A1 WO 2015037509A1 JP 2014073317 W JP2014073317 W JP 2014073317W WO 2015037509 A1 WO2015037509 A1 WO 2015037509A1
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WIPO (PCT)
Prior art keywords
sliding
layer
powder
base layer
sintered
Prior art date
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PCT/JP2014/073317
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English (en)
Japanese (ja)
Inventor
洋介 須貝
容敬 伊藤
敏彦 毛利
古森　功
Original Assignee
Ntn株式会社
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Filing date
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Priority claimed from JP2013186993A external-priority patent/JP6228409B2/ja
Priority claimed from JP2014020343A external-priority patent/JP2015148249A/ja
Priority claimed from JP2014153710A external-priority patent/JP2016030848A/ja
Application filed by Ntn株式会社 filed Critical Ntn株式会社
Priority to US14/917,291 priority Critical patent/US20160215820A1/en
Priority to CN201480049470.5A priority patent/CN105555445B/zh
Priority to EP14843976.3A priority patent/EP3045241A4/fr
Priority to KR1020167005785A priority patent/KR20160054470A/ko
Publication of WO2015037509A1 publication Critical patent/WO2015037509A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
    • F16C33/128—Porous bearings, e.g. bushes of sintered alloy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F5/10—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
    • B22F5/106—Tube or ring forms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/011—Layered products comprising a layer of metal all layers being exclusively metallic all layers being formed of iron alloys or steels
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0207—Using a mixture of prealloyed powders or a master alloy
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0207—Using a mixture of prealloyed powders or a master alloy
    • C22C33/0214—Using a mixture of prealloyed powders or a master alloy comprising P or a phosphorus compound
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C24/00—Coating starting from inorganic powder
    • C23C24/08—Coating starting from inorganic powder by application of heat or pressure and heat
    • C23C24/082—Coating starting from inorganic powder by application of heat or pressure and heat without intermediate formation of a liquid in the layer
    • C23C24/085—Coating with metallic material, i.e. metals or metal alloys, optionally comprising hard particles, e.g. oxides, carbides or nitrides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/04—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings of inorganic non-metallic material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
    • C23C8/64—Carburising
    • C23C8/66—Carburising of ferrous surfaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
    • F16C33/122—Multilayer structures of sleeves, washers or liners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/14—Special methods of manufacture; Running-in
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/14—Special methods of manufacture; Running-in
    • F16C33/145—Special methods of manufacture; Running-in of sintered porous bearings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F3/03—Press-moulding apparatus therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2220/00—Shaping
    • F16C2220/20—Shaping by sintering pulverised material, e.g. powder metallurgy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2223/00—Surface treatments; Hardening; Coating
    • F16C2223/30—Coating surfaces

Definitions

  • the present invention relates to a sliding member having a sliding surface that slides with another member, and a method for manufacturing the same.
  • Patent Document 1 discloses a sintered bearing in which copper is dispersed in an iron-carbon alloy containing a martensite structure as a bearing for a construction machine. In this sintered bearing, the entire sintered body is quenched (for example, oil-quenched) after sintering, and then the inner and outer peripheral surfaces and end surfaces are cut and ground to finish to a predetermined size.
  • Japanese Patent Application Laid-Open No. 2004-228561 describes a method for forming the green compact. Specifically, the outer peripheral surface side of the green compact is formed with a high-strength first powder, and the inner peripheral surface side is formed with a second powder excellent in low friction, and then the green compact is sintered. I am going to conclude.
  • an object of the present invention is to provide a sliding member capable of improving the slidability and durability of the sliding surface while ensuring the strength of the sintered body, and a method for manufacturing the same.
  • the present invention is a sliding member that is formed of a sintered body and has a sliding surface that slides on other members, and contains Fe, Cu, and C containing alloy elements as main components. And a base layer containing, as a main component, a low-melting-point metal having a lower melting point than Fe, Cu, Cu, and C as a main component, sintered together with the sliding layer in contact with the sliding layer.
  • the sliding layer is provided with a sliding surface.
  • This sliding member can be used, for example, as a bearing for a joint portion of an arm of a construction machine.
  • the base layer contains Cu and a low melting point metal
  • the low melting point metal contained in the base layer is first melted during sintering.
  • the melt of the low melting point metal diffuses deep inside the Fe particles by capillary action.
  • the melt of the low melting point metal wets the surface of the Cu particles, the Cu melts at a temperature lower than the melting point, and the molten Cu and the low melting point metal penetrate into the Fe particles and diffuse into the Fe particles. .
  • the Fe particles are firmly bonded to each other and the strength of the base layer is improved, so that the bearing strength can be ensured even when the sintering temperature is lowered.
  • the sintering temperature By setting the sintering temperature to a temperature lower than the melting point of Cu, the Cu particles contained in the sliding layer are not melted even during the sintering, and the solid state is maintained. Therefore, Cu particles contained in the sliding layer are not drawn into the base layer, and it is possible to distribute a target amount of Cu structure on the sliding surface. From the above, it is possible to achieve both the slidability on the sliding surface and the strength of the sintered body.
  • this sliding member contains an element (at least one selected from Ni, Mo, Mn, and Cr) that improves hardenability as an alloy element contained in the sliding layer, carburizing and quenching, etc.
  • an element at least one selected from Ni, Mo, Mn, and Cr
  • at least a part of the Fe structure of the sliding layer can be martensitic and bainite transformed in the cooling process after sintering (sinter hardening).
  • the sliding layer containing a sliding surface is hardened, the abrasion resistance of a sliding surface can be improved.
  • the strength of the base layer is increased by penetration and diffusion of Cu and low melting point metal into Fe particles in the base layer, the strength of the entire sintered body is improved. Accordingly, the impact load is frequently applied, and it can be used as a sliding member used under a high surface pressure, for example, a bearing used in a joint part of an arm of a construction machine.
  • the base layer that occupies most of the sintered body basically does not contain the above alloy elements, the majority of the base layer is not sintered hardened even after cooling, and therefore the Fe of the base layer The structure does not undergo martensitic transformation or bainite transformation.
  • the base layer is softer than the sliding layer, it is possible to correct the size of the sintered body by sizing (a step of compressing and shaping the sintered body in a mold).
  • Patent Document 1 since the entire sintered body is cured by oil quenching after sintering, dimensional correction of the sintered body is inevitably performed by machining such as cutting and grinding.
  • the sliding member can be dimensionally corrected by sizing, and machining is not necessary. Moreover, the quenching process after sintering is unnecessary. Thus, since the quenching process and machining process after sintering can be omitted, the cost of the sliding member can be further reduced as compared with the invention described in Patent Document 1.
  • the concentration of the low melting point metal in the base layer is preferably in the range of 0.1 to 0.6 wt%.
  • the Cu concentration of the sliding layer 10 wt% or more and 30 wt% or less it is possible to prevent the cost increase due to excessive use of copper while ensuring the sliding performance of the sliding surface.
  • the sintered body is sintered at a temperature lower than the melting point of Cu and higher than the reaction temperature of Fe and C, the copper contained in the sliding layer is not melted completely during the sintering and is in a solid state. Can be maintained, and the slidability of the sliding layer can be improved. Further, since Fe and C react to form a hard pearlite phase (partially a ferrite phase) in the Fe structure, the strength of the base layer can be ensured.
  • the sliding layer can also be formed in a partially cylindrical shape with a cross section orthogonal to the axial direction.
  • the sliding surface to be copper-rich is formed not in the entire circumferential direction of the sintered body but only in a partial region in the circumferential direction.
  • the usage-amount of expensive copper can be suppressed and cost reduction of a sintered bearing can be achieved.
  • the shaft When the sliding member is used as a bearing, the shaft rarely slides with the entire inner peripheral surface of the sliding member, and the sliding region of the sliding member with the shaft is partially affected by gravity. It is often limited to a region. Therefore, if the sliding member is fixed to the housing after adjusting the orientation and orientation so that the sliding surface of the sliding layer is located in this limited partial area, the shaft is stably supported by the sliding surface. can do.
  • the sliding member described above prepares a first powder containing Fe, Cu, a metal having a lower melting point than Cu, and C as main components, and contains Fe, Cu, and C containing alloy elements as main components.
  • a second powder is prepared, a partition member is arranged in the mold to form a first cavity and a second cavity, the first powder is filled in the first cavity, and the second powder is filled in the second cavity.
  • the composition corresponding to the first powder is filled, and the first powder and the second powder in the mold are simultaneously compressed with the partition member removed to form a green compact, and the green compact is sintered.
  • the base layer and the sliding layer having a composition corresponding to the second powder are formed, and then the obtained sintered body is subjected to sizing and oil impregnation.
  • the green compact When molding the green compact by simultaneously compressing the first powder and the second powder, if the difference in apparent density between the two powders is large, the green compact will be hindered.
  • the green compact can be formed by making the thickness of the base layer larger than the thickness of the sliding layer and making the apparent density of the first powder smaller than the apparent density of the second powder. . That is, the green compact can be easily formed even if there is a slight difference in the apparent density between the first powder and the second powder.
  • a sintered bearing is given as an example of the sliding member of the present invention, and an embodiment thereof will be described below with reference to the drawings.
  • the sintered bearing according to the present invention is suitable for use in a joint portion that connects arms (including booms and buckets) of construction machines such as excavators and bulldozers.
  • FIG. 1 shows the schematic structure of such a joint. As shown in FIG. 1, in this joint part, the tip of the second arm 7 is inserted inside the first arm 6 formed in a bifurcated shape. A mounting hole 7a is provided at the tip of the second arm 7, and an outer peripheral surface 1b of the sintered bearing 1 made of a sintered body is fixed to the mounting hole 7a by using appropriate mounting means such as press fitting.
  • the first arm 6 and the second arm 7 are rotatably connected by inserting the pin 4 into the pin hole 6a provided in each of the bifurcated portions of the first arm 6 and the inner peripheral surface 2a of the sintered bearing 1. .
  • the pin 4 is fixed to the first arm 6. Therefore, when the first arm 6 and the second arm 7 are swung relative to each other, the pin 4 rotates relative to the inner peripheral surface 1 a of the bearing 1.
  • Reference numeral 8 is a stopper that prevents the pin 4 from coming off. In this joint portion, the head 4a or the retaining member 8 of the pin 4 is removed from the shaft portion of the pin 4, and the first arm 6 and the second arm 7 are separated by removing the pin 4, and maintenance of the bearing 1 and the pin 4 is performed. Can be done.
  • the sintered bearing 1 is formed of a cylindrical sintered body, and the sliding layer 2 on the inner diameter side and the base layer 3 on the outer diameter side are in contact with each other. These are integrated.
  • the sintered bearing 1 comprises only the sliding layer 2 and the base layer 3, and each layer has a cylindrical shape, particularly a cylindrical shape.
  • the inner peripheral surface 1a of the sintered bearing 1 (the inner peripheral surface of the sliding layer 2) has a straight circular section in the axial direction, and the shaft portion of the pin 4 (hereinafter referred to as the shaft 4) inserted into the inner periphery.
  • the sliding surface A (bearing surface) is supported so as to be relatively rotatable.
  • the outer peripheral surface 1b of the sintered bearing 1 (the outer peripheral surface of the base layer 3) has a perfect cross-sectional shape that is straight in the axial direction, and constitutes a mounting surface B that is attached to other members such as the second arm 7. Both axial end surfaces of the sintered bearing 1 are flat surfaces extending in a direction orthogonal to the axial direction. Chamfering is provided between both axial end surfaces of the sintered bearing 1 and the inner peripheral surface 2a and the outer peripheral surface 3a.
  • the sintered bearing 1 When used in the above joint, the sintered bearing 1 is formed, for example, so that the inner diameter is 30 to 100 mm and the thickness in the radial direction is 5 to 50 mm.
  • the thickness of the sliding layer 2 in the radial direction is about 1 to 20% (preferably about 2 to 10%) of the thickness of the sintered bearing 1 in the radial direction. About 2 mm. If the sliding layer 2 is too thin, the filling ability of the raw material powder at the time of molding is deteriorated and the allowable wear limit is lowered. If the sliding layer 2 is too thick, an element for improving hardenability, which will be described later, This is because the amount of copper used increases and costs increase.
  • the fine pores of the sintered bearing 1 having a porous shape are impregnated with a lubricating oil such as mineral oil or synthetic oil as a lubricant.
  • a lubricating oil such as mineral oil or synthetic oil as a lubricant.
  • the lubricating oil retained in the internal pores of the sintered bearing 1 oozes out from the surface opening of the inner peripheral surface 1a of the sintered bearing 1, and the inner peripheral surface 1a Since an oil film of lubricating oil is formed between the shaft 4 and the inner peripheral surface 1a, wear is suppressed or prevented.
  • the oil content of the entire sintered bearing 1 is, for example, 10 to 25 vol%, preferably 15 to 25 vol%.
  • the oil content is less than 10 vol%, the desired lubrication characteristics cannot be stably maintained and exhibited over a long period of time. If the oil content exceeds 25 vol%, the internal porosity increases, so sintering. This is because the mechanical strength required for the bearing 1 may not be ensured.
  • the lubricating oil impregnated in the sintered bearing 1 is too low in viscosity, the lubricating oil is likely to flow out of the bearing, and an oil film having a predetermined strength is formed between the inner peripheral surface 1a and the shaft 4.
  • the inner peripheral surface 1a is likely to wear.
  • the lubricating oil is too high in viscosity, the amount of lubricating oil oozing out from the surface opening of the inner peripheral surface 1a is insufficient, and wear of the inner peripheral surface 1a may be promoted.
  • the lubricating oil a kinematic viscosity at 40 ° C., preferably not less 5 mm 2 / s or more 600 mm 2 / s, more preferably not less 50 mm 2 / s or more 550mm 2 / s, 100mm 2 / More preferably, s is 500 mm 2 / s or less.
  • liquid grease as the lubricant to be impregnated into the internal pores of the sintered bearing 1 in place of the above lubricating oil.
  • a lubricating oil having a kinematic viscosity at 40 ° C. within the above range is used as a base oil, and a soap-based thickener such as lithium soap or a non-soap-based thickener such as urea is added thereto. Things can be used.
  • the sintered bearing 1 of the present invention has a two-layer structure in which the metal composition is different between the sliding layer 2 and the base layer 3.
  • the sintered bearing 1 having a two-layer structure is manufactured by sequentially performing a compression molding process, a sintering process, a sizing process, and an oil impregnation process described below.
  • a so-called two-color molding technique is adopted in which the material of the sliding layer 2 and the material of the base layer 3 are supplied to the same mold (die) and molded simultaneously.
  • This two-color molding is one in which two cavities are formed on the outer diameter side and the inner diameter side in the mold, and each cavity is filled with powder, and is performed using, for example, a mold shown in FIG.
  • the mold includes a die 11, a core pin 12 disposed on the inner periphery of the die 11, an outer lower punch 13 disposed between the inner peripheral surface 11a of the die 11 and the outer peripheral surface 12a of the core pin 12, and a partition It has the member 14, the inner lower punch 15, and the upper punch 16 (refer FIG. 7).
  • the outer lower punch 13, the partition member 14, and the inner lower punch 15 have a concentric cylindrical shape and can be moved up and down independently.
  • the partition plate 14 and the inner lower punch 15 are raised to the upper end position, and the outer lower punch 13 is lowered to the lower end position, so that the inner peripheral surface 11 a of the die 11 and the outer periphery of the partition plate 14 are
  • a first cavity 17 on the outer diameter side is formed by the surface 14 a and the end surface 13 a of the outer lower punch 13.
  • the first cavity 17 is filled with the first powder M1 corresponding to the base layer 3.
  • the composition of the first powder M1 will be described later.
  • the inner lower punch 15 is lowered to the lower end position, and the inner peripheral surface 14 b of the partition plate 14, the outer peripheral surface 12 a of the core pin 12, and the end surface 15 a of the inner lower punch 15
  • a second cavity 18 is formed.
  • the second cavity 18 is formed in a state of being isolated from the first cavity 17, and the second powder 18 is filled in the second cavity 18 corresponding to the sliding layer 2.
  • the second powder M2 overflows from the inner cavity 18 so as to cover the upper side of the partition plate 14.
  • the composition of the second powder M2 will be described later.
  • the partition plate 14 is lowered as shown in FIG. Thereby, the second powder M2 enters the space corresponding to the partition member 14, and the first powder M1 and the second powder M2 are slightly mixed and contacted.
  • the cavity 19 formed by the inner peripheral surface 11a of the die 11, the end surface 13a of the outer lower punch 13, the end surface 14c of the partition plate 14, the end surface 15a of the inner lower punch 15, and the outer peripheral surface 12a of the core pin 12 is The first powder M1 and the second powder M2 are filled in a two-layer state. Then, excess second powder M2 overflowing from the cavity 19 is removed (see FIG. 6).
  • the upper punch 16 With the partition member 14 removed from the mold in this way, as shown in FIG. 7, the upper punch 16 is lowered, and the end face 16a of the upper punch 16 is pressed against the powders M1, M2, and the upper punch 16, The powders M1 and M2 filled in the cavity 19 are compressed by the punches 13 and 15, the partition member 14, and the die 11, and the green compact M is formed. And as shown in FIG. 8, the outer lower punch 13, the partition plate 14, and the inner lower punch 15 are raised, and the green compact M is taken out from the mold.
  • the first powder M1 corresponding to the base layer 3 is mainly composed of iron powder, copper powder and graphite powder, and additionally contains a low melting point metal.
  • iron powder reduced iron powder, atomized iron powder, and the like can be used, but it is preferable to use porous reduced iron powder having excellent oil impregnation.
  • copper powder electrolytic copper powder or atomized copper powder can be used, but if the electrolytic copper powder having a dendritic shape as a whole particle is used, the green compact strength can be increased, and copper can be used during sintering. Is more preferable because it easily diffuses into the Fe particles.
  • the low melting point metal a metal having a melting point smaller than that of copper, specifically, a metal having a melting point of 700 ° C. or lower, such as tin (Sn), zinc (Zn), phosphorus (P), etc. can be used.
  • This low-melting-point metal can be added by using a powder alloyed with iron in addition to adding the simple powder to the mixed powder.
  • phosphorus is easily diffused into iron and can be diffused into the iron particles, and further promotes copper diffusion. That is, compatibility with both iron and copper is good. Therefore, it is preferable to use phosphorus as the low melting point metal.
  • iron-phosphorus alloy powder Fe 3 P
  • the advantages of easy mixing and forming of the first powder M1 and high safety are obtained.
  • the blending amount of each powder in the first powder M1 is preferably, for example, copper powder: 2-5 wt%, graphite powder: 0.5-0.8 wt%, and the rest is an iron-low melting point metal alloy steel powder. .
  • the ratio of the low melting point metal in the first powder M1 is 0.1 to 0.6 wt% (preferably 0.3 to 0.5 wt%).
  • Copper powder functions as a binder that binds iron powders. If the amount of copper powder is too small, the strength of the base layer 3 is reduced, and if too large, the diffusion of carbon is inhibited and the strength of the sintered body is reduced. -Since the hardness is reduced, the above range is adopted.
  • the low melting point metal is blended in order to increase the strength of the sintered body through the diffusion of the iron into its own iron particles and further the diffusion of copper into the iron particles. If the amount is too large, the low melting point metal segregates and the sintered body becomes brittle, leading to a decrease in strength.
  • Graphite powder is blended to form a hard pearlite phase by reacting iron and carbon during sintering. If the amount is too small, the strength of the base layer cannot be secured, and if it is too large, the iron becomes a cementite structure. Since it becomes brittle and causes a decrease in strength, the above range is adopted.
  • the second powder M2 corresponding to the sliding layer 2 is a mixture of iron powder (alloy steel powder) containing alloy elements, copper powder, and graphite powder.
  • the alloy element an element that improves hardenability, specifically, any one or more selected from Ni, Mo, Mn, and Cr is used.
  • Ni and Mo are selected, and Ni, Mo and iron alloy steel powder (Fe—Ni—Mo alloy steel powder) is used.
  • Elements that improve hardenability are added to cause martensite transformation and bainite transformation as described later to perform sintering hardening, but Ni and Mo are particularly effective in improving hardenability.
  • Complete alloy powder is preferable as the alloy steel powder of the second powder M2.
  • the copper powder is preferably electrolytic copper powder, but atomized copper powder may be used.
  • the amount of each powder in the second powder M2 is 10 to 30 wt% (preferably 15 to 20 wt%) of copper powder and 0.2 to 1.0 wt% (preferably 0.3 to 0.8 wt%) of graphite powder. The remainder is preferably alloy steel powder. Further, the ratio of Ni in the second powder M2 is 1.0 to 4.0 wt% (preferably 1.5 to 3.5 wt%), and the ratio of Mo is 0.5 to 2.0 wt% (preferably 0.8. The type and amount of alloy steel powder are selected so as to be in the range of 5 to 1.5 wt%. The blending amounts of Ni and Mo are determined from the effect of improving formability and hardenability. If the amount of copper is too small, the slidability of the sliding surface 2a is lowered.
  • the graphite powder of the second powder M2 is blended to react mainly with iron and carbon during sintering to form a martensite phase and a bainite phase, and further to function as a solid lubricant.
  • the upper limit of the blending ratio The lower limit is determined for the same reason as that for determining the blending ratio of the graphite powder in the first powder M1.
  • the apparent densities of the first powder M1 corresponding to the base layer 3 and the second powder M2 corresponding to the sliding layer 2 are both 1.0 to 4.0 g / cm 3 . Due to the difference in the composition of the two powders, the apparent density of the two powders inevitably varies. From this difference, the compact M collapses when the first powder M1 and the second powder M2 are simultaneously molded in the compression molding process. Therefore, it is expected that the molding becomes difficult.
  • the thickness of the sliding layer 2 is sufficiently smaller than the thickness of the base layer 3 (as described above, the thickness of the sliding layer 2 is 1 to 20 of the thickness of the sintered bearing).
  • the difference in density is 0.5 g / cm 3 or less.
  • the green compact M can be formed even if the first powder M1 and the second powder M2 are simultaneously formed. Therefore, it is preferable that the apparent density of the first powder M1 is smaller than the apparent density of the second powder M1, and the density difference is suppressed to 0.5 g / cm 3 or less.
  • Sintered body M ′ is obtained by sintering the green compact M that has undergone the compression molding process described above in the sintering process (see FIG. 11). At this time, since the base layer 3 is sintered together with the sliding layer 2 in contact with the sliding layer 2, the sliding layer 2 and the base layer 3 can be integrated after sintering.
  • a continuous sintering furnace 20 having a sintering zone 20a in which a heater 21 is installed and a cooling zone 20b for performing natural heat dissipation can be used.
  • An atmosphere gas containing CO is used.
  • the sintering temperature (temperature in the sintered structure) is set to be lower than the melting point of copper (1083 ° C.) and higher than the temperature at which iron and carbon start reaction (about 900 ° C.).
  • the furnace temperature is set to 1000 ° C. to 1110 ° C., for example. This temperature is lower than a general furnace temperature (1130 ° C. or higher) when sintering an iron-based sintered body.
  • the sintered body M ′ that has undergone the sintering process is transferred to the sizing process and dimension correction is performed.
  • the inner peripheral surface, outer peripheral surface, and both end surfaces of the sintered body M ′ are formed using a sizing die having a die 23, a core rod 24, and upper and lower punches 25 and 26.
  • the sintered body M ′ is sized.
  • the sintered bearing 1 is completed by impregnating the internal pores of the sintered body M ′ with a lubricant in the oil impregnation process.
  • the sintered body M ′ may be tempered after the sintering.
  • phosphorus contained in the first powder M1 is melted.
  • the phosphorus melt diffuses deep inside the Fe particles by capillary action.
  • the phosphorus melt wets the surface of the Cu particles, the Cu melts at a temperature below its melting point, and the molten Cu and phosphorus penetrate into the Fe particles and diffuse into the Fe particles. Thereby, iron particles are firmly bonded to each other, and the strength of the base layer 3 is improved.
  • sintering is performed at a temperature higher than the reaction start temperature of iron and carbon, a hard pearlite phase is formed in the Fe structure (partially a ferrite phase).
  • the strength of the base layer 3 is ensured. Therefore, even when the sintering temperature is lower than the sintering temperature of a general iron-based sintered product as described above, the base layer 3 The strength required for 3 can be ensured.
  • the copper contained in the sliding layer 2 (second powder M2) does not melt even during the sintering and maintains a solid state. Therefore, the copper existing on the sliding layer 2, particularly the sliding surface A, is not drawn into the base layer 3, and a target amount of copper can be distributed on the sliding surface A. Therefore, both the slidability of the sliding surface A and the strength of the sintered body M ′ can be achieved.
  • the cooling layer 20b of the continuous sintering furnace 20 shown in FIG. since the hardenability improving elements such as Ni and Mo are included in the sliding layer 2, the cooling layer 20b of the continuous sintering furnace 20 shown in FIG. In the meantime, martensite transformation and bainite transformation can be caused in the Fe structure of the sliding layer 2 to increase the hardness (sinter hardening). Thereby, the sliding surface A can be hardened and its wear resistance can be improved.
  • the strength of the base layer 3 is increased by diffusion of copper and phosphorus in the base layer 3, the strength of the entire sintered body (compression strength, etc.) is improved. Therefore, the impact load is frequently applied, and can be used as a bearing in the joint portion of the arm of the construction machine used under high surface pressure.
  • the sintered body M ′ of the invention can be dimensionally corrected by sizing, and does not require post-processing by machining. Moreover, even if it does not quench after sintering, sufficient intensity
  • strength for example, crushing strength of 500 Mpa or more
  • strength for example, crushing strength of 500 Mpa or more
  • the cost of the sintered bearing 1 can be further reduced as compared with the invention described in Patent Document 1.
  • the surface hardness of the sliding layer 2 (bearing surface A) after the sizing is 85 or more, preferably 90 or more according to the Rockwell F scale (HRF) defined in “JIS Z2245: 2011”. More preferably, it is 95 or more. Further, the surface hardness of the base layer 3 after sizing is about 55 to 85 on the Rockwell hardness F scale.
  • HRF Rockwell F scale
  • the graphite in the base layer 3 is decomposed by sintering, basically becomes all carbon and reacts with Fe.
  • some of the graphite in the sliding layer 2 remains as particles even after sintering. This is because the sliding layer 2 has a higher copper content than the base layer 3, and the copper particles cover a part of the surface of the iron particles, which makes it difficult for Fe and C to react.
  • the sliding layer 2 has more graphite particles than the base layer 3, the graphite particles can function as a solid lubricant, and the sliding property of the sliding surface A is improved. be able to.
  • the first powder M1 corresponding to the base layer 3 does not contain elements (Ni and Mo in this embodiment) that improve the hardenability, so that the base layer 3 does not contain these elements in theory.
  • elements Ni and Mo in this embodiment
  • the base layer 3 does not contain these elements in theory.
  • a region containing an element that improves the hardenability is formed in the vicinity of the interface, so that the strength of the interface, and hence the bonding strength between the sliding layer 2 and the base layer 3 is increased.
  • a region sufficiently separated from the sliding layer 2 in the base layer 3, for example, a surface facing the sliding layer 2 (in this embodiment, the outer peripheral surface of the base layer 3) is hardened.
  • the element to improve is not included.
  • the radial dimension of the region R (concentration gradient layer) where the concentration gradient occurs is in the range of 0.1 to 1.0 mm, preferably in the range of 0.2 to 0.5 mm.
  • the radial dimension of the concentration gradient layer R can be adjusted by the radial thickness of the partition member 14 (see FIG. 3) of the two-color molding die.
  • the sliding layer 3 theoretically does not contain a low melting point metal. However, for the same reason as described above, a low-melting-point metal concentration gradient is generated at the interface between the sliding layer 2 and the base layer 3. In the sliding layer 2, a region sufficiently separated from the base layer 3, for example, a surface facing the base layer 3 (sliding surface A of the sliding layer 2 in this embodiment) has a low melting point metal. It will not be included.
  • the microstructure of the sliding layer 2 is schematically shown in FIG. 13A
  • the microstructure of the base layer 3 is schematically shown in FIG. 13B.
  • the sliding layer 2 is mainly composed of an Fe structure based on Fe, a Cu structure made of only copper represented by a dotted pattern, and a graphite structure shown by black coating.
  • Fe structure is more than Cu structure and graphite structure is the smallest.
  • the Fe structure mainly includes a martensite phase and a bainite phase, and forms a quenched structure including a pearlite phase in part. Ni and Mo are diffused in the quenched structure.
  • the sliding layer 2 follows the mixing ratio of the second powder M2, and contains Cu: 10 to 30 wt% (preferably 15 to 20 wt%), C: 0.5 to 0.8 wt%, Ni: 1.5 as the main components. It is an iron-based metal structure containing ⁇ 3.5 wt%, Mo: 0.5 to 1.5 wt%, with the balance being Fe and inevitable impurities.
  • the base layer 3 is composed of an Fe structure (pearlite phase and ferrite phase) having Fe as a base material. Cu and P are diffused inside this Fe structure, and Cu as particles does not exist in the base layer 3. Moreover, there is no hardened structure and graphite structure.
  • This base layer 3 follows the mixing ratio of the first powder M1, and contains as main components Cu: 2 to 5 wt%, P: 0.1 to 0.6 wt% (preferably 0.3 to 0.5 wt%), C : An iron-based metal structure containing 0.5 to 0.8 wt%, with the balance being Fe and inevitable impurities. Since the copper content of the base layer 3 is less than the copper content of the sliding layer 2, it is possible to reduce the cost by reducing the amount of copper used in the entire bearing.
  • the sliding surface A is formed on the inner peripheral surface of the sliding layer 2
  • the present invention is not limited to this.
  • the present invention may be applied to the sintered bearing 1 on which the sliding surface A is formed.
  • the sliding layer 2 is formed on the outer diameter side of the sintered bearing 1, and the outer peripheral surface of the sliding layer 2 constitutes the sliding surface A.
  • the base layer 3 is formed on the inner diameter side of the sintered bearing 1, and the inner peripheral surface of the base layer 3 constitutes the mounting surface B.
  • the configurations and functions of the sliding layer 2 and the base layer 3 are common to the sliding layer 2 and the base layer 3 in the above-described embodiment.
  • a sliding surface A can be formed on the end surface of the sintered bearing.
  • FIG. 15 conceptually shows a cross section of the joint portion of the arm of the construction machine, as in FIG.
  • the first arm 6 is located closer to the arm tip than the second arm 7.
  • the pin 4 fixed to the first arm 6 falls relatively downward due to gravity acting on the first arm 6.
  • the pin 4 serving as a shaft is supported in the lower region of the inner peripheral surface 1a of the sintered bearing 1, and therefore, when the two arms 6 and 7 are relatively rotated, the inner periphery of the sintered bearing 1 is mainly used.
  • the pin 4 slides with respect to the lower region of the surface 1a.
  • the sliding layer 2 is formed in a partial cylindrical shape (semi-cylindrical shape) that is terminated in a cross section (transverse cross section) orthogonal to the axial direction.
  • the sliding surface A on the inner periphery of the sliding layer 2 also has a partial cylindrical surface shape (in the illustrated example, a semi-cylindrical surface shape) that has an end in the cross section.
  • the base layer 3 integrally includes a thin portion 31 that is thin in the radial direction and a thick portion 32 that is thick in the radial direction, and a circumferential region in which the sliding layer 2 does not exist constitutes the thick portion 32.
  • the sliding surface A of the sliding layer 2 and the inner peripheral surface of the thick portion 32 constituting the base layer 3 constitute an inner peripheral surface 1a of the sintered bearing 1, and the outer peripheral surface of the base layer 3 is a sintered bearing. 1 outer peripheral surface 1b (attached surface B) is formed.
  • the pin 4 falls due to gravity and slides with respect to the lower region of the inner peripheral surface 1a of the sintered bearing 1, so that the sintered bearing 1 has the sliding layer 2
  • the sliding surface A is attached to the attachment hole 7a of the second arm 7 in such a direction or posture as to cover the lower region of the pin 4. Thereby, the pin 4 can be stably supported by the sliding layer 2 over a long period of time.
  • FIG. 17 shows a mold used in the compression molding process of the sintered bearing 1 of this embodiment. Similar to the mold shown in FIG. 3, the mold includes a die 11, a core pin 12, a first lower punch 13, a partition member 14, a second lower punch 15, and an upper punch (not shown).
  • the partition member 14 forms a second cavity 18 having a shape (partial cylindrical shape) corresponding to the shape of the semi-cylindrical sliding layer 2.
  • the mold configuration and the molding procedure in this compression molding process are the same as those in the compression molding process shown in FIGS. 3 to 8 except for the shape of the partition member 14, and the description thereof will be omitted.
  • the same reference numerals as those in the drawings are attached to portions common to the respective parts of the mold shown in FIGS.
  • the sliding layer 2 with much content of copper and also the element which improves hardenability is not the whole periphery of the internal peripheral surface 1a of the sintered bearing 1, but the circumferential direction partial region. Only formed. Therefore, it is possible to reduce the cost of the sintered bearing 1 by suppressing the amount of expensive copper and hardenability improving elements used.
  • the sintered bearing 1 is constituted by the sliding layer 2 and the base layer 3 having different compositions.
  • the sintered bearing 1 shown in FIG. 1 includes an inner diameter layer 5 that is sintered together with the sliding layer 2 and the base layer 3 in addition to the sliding layer 2 and the base layer 3.
  • the sliding layer 2 and the inner diameter layer 5 are both formed in a semi-cylindrical shape, and the base layer 3 is formed in a cylindrical shape.
  • the sliding layer 2 and the inner diameter layer 5 are continuous in the circumferential direction, the semi-cylindrical sliding surface A of the sliding layer 2 and the inner cylindrical surface of the inner diameter layer 5 are sintered.
  • a cylindrical inner peripheral surface 1a of the connection bearing 1 is configured.
  • the radial thicknesses of the sliding layer 2 and the inner diameter layer 5 are equal in the radial direction, so that the radial thickness of the base layer 3 is constant in each part in the circumferential direction.
  • the sliding layer 2 is disposed in the lower region, which is the direction in which the pin 4 falls, and the sliding surface A of the sliding layer 2 falls downward in the bearing gap. The rotation of the pin 4 is supported.
  • FIG. 19 and FIG. 20 show a transverse sectional view (axial orthogonal sectional view) and a longitudinal sectional view (axial parallel sectional view) of the sintered bearing 1 according to the fourth embodiment.
  • the sintered bearing 1 is made of a metal sintered body having a cylindrical shape as a whole, and is used, for example, in a joint portion of an arm of a construction machine shown in FIG.
  • the inner peripheral surface 1a of the sintered bearing 1 is formed in a cylindrical shape, and the cylindrical inner peripheral surface 1a is used to relatively connect the shaft 4 (for example, a connecting pin for connecting the arms) inserted in the inner periphery. Supports free movement.
  • the cylindrical inner peripheral surface 1a of the sintered bearing 1 functions as a sliding surface A that slides with other members.
  • the sintered sintered bearing 1 integrally includes an intermediate portion 301 and a pair of surface layer portions 201 and 202 disposed on both sides in the radial direction of the intermediate portion 301.
  • the surface layer portion 201 and the intermediate portion 301 on the inner diameter side, and the intermediate portion 301 and the surface layer portion 202 on the outer diameter side are joined together as the green compact is sintered.
  • the heel intermediate portion 301 is formed of the base layer 3 described above. Further, the surface layer portion 201 on the inner diameter side is formed by the sliding layer 2 described above.
  • the outer diameter side surface layer portion 202 is, for example, a cylinder containing Fe as a main component, Cu, alloy elements (Ni and Mo in this case) for improving hardenability, and C, as in the inner diameter side surface layer portion 201. Formed of sintered metal.
  • the concentration (mixing ratio) of each element constituting the outer diameter side surface layer portion 202 may be the same as or different from the concentration of each element constituting the inner diameter side surface layer portion 201.
  • the surface layer portion 201 on the inner diameter side has a sliding surface A that slides with the shaft 4, and therefore is formed of a sintered metal that is more slidable than the surface layer portion 202 on the outer diameter side.
  • the Cu concentration of the surface layer portion 201 on the inner diameter side is higher than the Cu concentration of the surface layer portion 202 on the outer diameter side.
  • the Fe structure included in both surface layer portions 201 and 202 causes martensitic transformation or bainite transformation after sintering. (Sinter hardening), these are hardened. As a result, it is possible to obtain the sliding surface A and the mounting surface B having high hardness and high wear resistance.
  • the sliding layer A having excellent slidability is obtained, and sliding with the shaft 4 is achieved. Wear of the sliding surface A due to repetition can be suppressed.
  • the heel intermediate portion 301 has a lower density than at least the surface layer portion 201 on the inner diameter side of the surface layer portions 201 and 202.
  • the lubricant held by the intermediate part 301 can be supplied to the surface layer part 201 on the inner diameter side by capillary force. Abundant lubricant is interposed between the outer peripheral surface of the shaft 4 and wear of the sliding surface A can be effectively suppressed or prevented.
  • the intermediate portion 301 having a lower density than the surface layer portion 201 on the inner diameter side, for example, as the molding powder of the intermediate portion 301, the average particle size (particularly the average particle size of Fe powder as the main component powder) What is necessary is just to use the thing larger than that of the powder for shaping
  • the intermediate portion 301 only needs to have a function as a lubricating oil layer for supplying a lubricant to the surface layer portion 201 on the inner diameter side, so that it is necessary for the surface layer portion 201 on the inner diameter side. Mechanical strength, wear resistance, slidability, etc. are unnecessary. Therefore, the amount of Cu included in the intermediate portion 301 is sufficient to allow the Fe particles to be bonded with the minimum required bonding strength.
  • the intermediate portion 301 does not contain an alloy element that improves hardenability, sintering hardening is not performed during sintering. Therefore, the intermediate part 301 can be made softer than the surface layer part 201 on the inner diameter side and the surface layer part 202 on the outer diameter side. In this case, since the intermediate portion 301 can be used as a deformation absorbing portion of the sintered bearing 1, even if the sintered bearing 1 is press-fitted and fixed to the hole portion 7a of the arm, the shape / dimensional accuracy of the sliding surface A As a result, it is difficult to adversely affect the shaft 4 and the support accuracy of the shaft 4 is improved.
  • the first powder M1 which is a powder for forming the outer diameter side surface layer portion 202
  • the first powder M1 is a powder for forming the outer diameter side surface layer portion 202
  • the second powder M2 that is the forming powder of the intermediate portion 301
  • the third powder M3 that is the forming powder of the surface layer portion 201 on the inner diameter side
  • the powder M1 to M3 are simultaneously compressed in the axial direction to form the green compact M.
  • This multicolor molding can be performed using, for example, the molding die apparatus 10 shown in FIGS.
  • the molding die apparatus 10 includes a die 11 that molds the outer diameter surface of the green compact M, a core pin 12 that is arranged on the inner periphery of the die 11 and molds the inner peripheral surface of the green compact M, and the die 11 and the core pin. 12, the first to third lower punches 13a to 13c and the first and second partition members 14a and 14b, which are arranged between the first and second end portions of the green compact M, and the other end surface of the green compact M.
  • the upper punch 15 is formed.
  • the lower punches 13a to 13c and the partition members 14a and 14b can be moved up and down independently.
  • the first lower punch 13a is lowered to the lower end while the second and third lower punches 13b, 13c and the partition members 14a, 14b are positioned at the upper end.
  • the first cavity 16 is formed by the inner peripheral surface of the die 11, the outer peripheral surface of the first partition member 14a, and the upper end surface of the first lower punch 13a, and the first powder M1 is formed in the first cavity 16.
  • the second lower punch 13b is lowered to the lower end, the inner peripheral surface of the first partition member 14a, the outer peripheral surface of the second partition member 14b, and the second lower punch 13b.
  • the second cavity 17 is formed on the upper end surface of the second cavities, and the second cavities 17 are filled with the second powder M2.
  • the second powder M2 overflows from the second cavity 17 and covers at least the upper part of the first partition member 14a. In the illustrated example, a partial region above the second partition member 14b is also covered with the second powder M2.
  • the first powder M1 corresponds to the metal composition of the outer diameter side surface portion 202
  • the second powder M2 is a powder corresponding to the metal composition of the intermediate portion 301.
  • the Fe powder that is the main component powder of the second powder M2 is the main component of the first powder M1.
  • a powder having a larger particle size than the Fe powder that is a powder, and further Fe powder that is a main component powder of the third powder M3 described later is used.
  • the third cavity 18 is formed, and the third cavity 18 is filled with the third powder M3 corresponding to the metal composition of the surface layer portion 201 on the inner diameter side.
  • the third powder M3 overflows from the third cavity 18 so as to cover at least a partial region above the second partition member 14b.
  • the second partition member 14a is covered with the space formed by removing the first partition member 14a.
  • the powder M2 is filled, and the first powder M1 and the second powder M2 are slightly mixed and contacted.
  • the space formed by removing the second partition member 14b is filled with the second powder M2 and the third powder M3 covering the second partition member 14b, and the second powder M2 is filled.
  • the third powder M3 are slightly mixed and contacted.
  • the cavity 19 formed by the inner peripheral surface of the die 11, the upper end surfaces of the lower punches 13a to 13c, the upper end surfaces of the partition members 14a to 14b, and the outer peripheral surface of the core pin 12 is the first powder M1, the first It will be in the state filled with 2 powder M2 and 3rd powder M3.
  • the upper punch 16 is lowered and the powders M1 to M3 filled in the cavity 19 are compressed in the axial direction.
  • a green compact M is formed.
  • the lower punches 13a to 13c and the partition members 14a to 14b are moved up and moved together to take out the green compact M from the molding die apparatus 10.
  • the green compact M obtained in the compression molding process described above is heated and sintered under predetermined conditions in the sintering process, whereby a sintered body M ′ (see FIG. 25) is obtained.
  • the green compact of the second powder M2 is in contact with the green compact of the first powder M1 and the green compact of the third powder M3.
  • the portion M2 ′ that becomes the intermediate portion 301 becomes the portion that becomes the surface layer portion 202 on the outer diameter side through the portion that becomes the concentration gradient layer R.
  • a sintered body M ′ integrated with M 1 ′ and the portion M 3 ′ which becomes the inner layer side surface layer 201 can be obtained.
  • the sintered body M ′ obtained in the flame sintering process is finished to a predetermined shape and size in the sizing process.
  • the sizing of the sintered body M ′ is performed by using a sizing die having a die 23, a core rod 24, and upper and lower punches 25, 26 arranged coaxially. This is performed by so-called sizing that compresses the radial surface, the internal diameter surface, and both end surfaces. With sizing, the surface hardness of the sintered body M ′ can be improved at the same time by work hardening, so that a sintered bearing 1 with higher strength can be realized.
  • the sintered bearing 1 shown in FIGS. 19 and 20 is completed.
  • a heat treatment (tempering) step for removing internal stress accumulated in the sintered body M ′ may be performed after the sizing step and before the oil impregnation step.
  • FIG. 26 shows an example thereof, and shows a sintered bearing 1 in which an intermediate portion 301 and two surface layer portions 201 and 202 are laminated in the axial direction.
  • the sintered bearing 1 is suitable for a purpose of rotatably supporting a shaft 4 that rotates at a high speed, such as a rotating shaft of a motor. Similarly, it is impregnated with lubricating oil.
  • both surface layer portions 201 and 202 can be formed of a sliding layer
  • the intermediate portion 301 can be formed of the base portion 3.
  • the inner peripheral surface 201 a of one surface layer portion 201 and the inner peripheral surface 202 a of the other surface layer portion 202 are formed to have a relatively small diameter to constitute a sliding surface A that supports the shaft 4.
  • the inner peripheral surface 301a of the intermediate portion 301 constitutes a so-called middle escape portion 28 having a relatively large diameter.
  • the thicknesses (axial dimensions) of the respective portions 201, 202, and 301 are formed to be substantially equal, but the thicknesses of the respective portions 201, 202, and 301 may be different from each other. For example, if the thickness of the intermediate portion 301 is sufficiently larger than the thickness of the surface layer portions 201 and 202, the amount of the alloy source used to improve the hardenability of the sintered bearing 1 as a whole is reduced, and the sintered bearing 1 can be reduced in cost.
  • a gradient layer R is provided, and each part 201, 202, 301 is substantially coupled via the concentration gradient layer R.
  • FIG. 27 shows an outline of a compression molding process when the sintered bearing 1 shown in FIG. 26 is manufactured.
  • the molding die apparatus 10 in the illustrated example has a cylindrical shape for molding the outer diameter surface of the green compact.
  • a die 11, a core pin 12 that molds the inner diameter surface of the green compact, and an upper punch 15 and a lower punch 13 that mold one end face and the other end face of the green compact are provided.
  • this molding die apparatus 10 for example, by lowering the lower punch 13, a cavity is formed on the inner peripheral surface of the die rod 11, the outer peripheral surface of the core pin 12, and the upper end surface of the lower punch 13.
  • the first powder M1 corresponding to one surface layer portion 201, the second powder M2 corresponding to the intermediate portion 301, and the third powder M3 corresponding to the other surface layer portion 202 are sequentially filled.
  • a dispersed layer in which the second powder M2 is dispersed in the first powder M1 is generated at a portion where the first powder M1 and the second powder M2 are in contact with each other.
  • a dispersed layer in which the third powder M3 is dispersed in the second powder M2 is generated.
  • the powder M1 to M3 is supplied to the molding die apparatus 30 by sequentially lowering the lower punch 13 in three stages to form cavities, and the cavities are sequentially filled with the first to third powders M1 to M3. This can be done.
  • the upper punch 15 is lowered to compress the powders M1 to M3 in the axial direction to form a green compact.
  • the lower punch 13 is moved up to take out the green compact from the molding die apparatus 10, and the taken out green compact is put into the sintering process. And this sintered compact is put into a sizing process and an oil impregnation process one by one, and the sintered bearing 1 is obtained.
  • sintering in a form in which two metal layers (sliding layer 2 and base layer 3) and three metal layers (two surface layer portions 201 and 202, intermediate portion 301) are laminated in the radial direction and the axial direction.
  • the bearing 1 is illustrated, it can be preferably applied to a sintered bearing in which four or more metal layers are laminated in the radial direction or the axial direction.
  • the form of the sintered body M ′ and the sliding surface A is also arbitrary, and the present invention can be applied to a spherical bush or a flat pad-like member (for example, a boom pad) as the sliding member.
  • the sliding surface A is spherical, and in the latter case, the sliding surface A is flat.
  • One or a plurality of recesses can be formed on the sliding surface A, whereby the recesses can be used as a lubricant reservoir.
  • the case where the interface between the sliding layer 2 and the base layer 3 is a cylindrical surface has been shown. (Not shown). Thereby, the bonding strength between the sliding layer 2 and the base layer 3 is further increased. Since the shape of the interface follows the shape of the partition member 14 (see FIG. 3 and the like) in the compression molding process, the shape of the interface can be changed by changing the shape of the partition member 14.
  • the sliding member of this invention is various uses for which a sliding surface becomes high surface pressure conditions. Applicable to.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Composite Materials (AREA)
  • Inorganic Chemistry (AREA)
  • Sliding-Contact Bearings (AREA)
  • Powder Metallurgy (AREA)

Abstract

L'invention concerne un élément coulissant (1) qui est composé d'un corps fritté. Le corps fritté comprend : une couche de coulissement (2) qui est principalement composée de fer (Fe), de cuivre (Cu) et de carbone (C) et contient au moins un élément d'alliage sélectionné parmi le nickel (Ni), le molybdène (Mo), le manganèse (Mn) et le chrome (Cr) ; et une couche de base (3) qui est frittée conjointement avec la couche de coulissement (2) tout en étant maintenue en contact avec la couche de coulissement (2), et qui est principalement composée de fer (Fe), de cuivre (Cu) et de carbone (C), et d'un métal présentant un point de fusion inférieur à celui du cuivre (Cu). La couche de coulissement (2) comporte une surface de coulissement (A) qui vient en contact coulissant avec un autre élément.
PCT/JP2014/073317 2013-09-10 2014-09-04 Élément coulissant et son procédé de production WO2015037509A1 (fr)

Priority Applications (4)

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US14/917,291 US20160215820A1 (en) 2013-09-10 2014-09-04 Sliding member and method for producing same
CN201480049470.5A CN105555445B (zh) 2013-09-10 2014-09-04 滑动部件及其制造方法
EP14843976.3A EP3045241A4 (fr) 2013-09-10 2014-09-04 Élément coulissant et son procédé de production
KR1020167005785A KR20160054470A (ko) 2013-09-10 2014-09-04 슬라이딩 부재 및 그 제조방법

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2013-186993 2013-09-10
JP2013186993A JP6228409B2 (ja) 2013-09-10 2013-09-10 摺動部材およびその製造方法
JP2014020343A JP2015148249A (ja) 2014-02-05 2014-02-05 焼結軸受
JP2014-020343 2014-02-05
JP2014153710A JP2016030848A (ja) 2014-07-29 2014-07-29 焼結金属部品
JP2014-153710 2014-07-29

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WO2016052064A1 (fr) * 2014-09-30 2016-04-07 Ntn株式会社 Élément de coulissement et procédé pour sa fabrication
US11619258B2 (en) * 2020-03-04 2023-04-04 Mahle International Gmbh Sliding bearing, method for producing a sliding bearing, internal combustion engine having a sliding bearing and electric machine having a sliding bearing
US20230227958A1 (en) * 2021-01-14 2023-07-20 Nsk Ltd. Method for carburizing steel member, steel component, and carburizing agent

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CN108788139A (zh) * 2014-04-22 2018-11-13 Ntn株式会社 粉末压坯的成型方法
JP6812113B2 (ja) * 2016-02-25 2021-01-13 Ntn株式会社 焼結含油軸受及びその製造方法
TWI644029B (zh) * 2016-06-30 2018-12-11 祥瑩有限公司 雙層滑動軸承
US10563695B2 (en) 2017-04-14 2020-02-18 Tenneco Inc. Multi-layered sintered bushings and bearings
CN109877316A (zh) * 2019-02-18 2019-06-14 益阳市再超粉末冶金有限公司 一种粉末冶金部件的模壁润滑模具及其制作方法
CN109865834A (zh) * 2019-02-19 2019-06-11 益阳市再超粉末冶金有限公司 一种汽车变速箱齿轮支架成型模具
CN109865840A (zh) * 2019-02-20 2019-06-11 益阳市再超粉末冶金有限公司 一种用粉末冶金材料制造汽车变速箱齿轮支架的方法
CN109794604B (zh) * 2019-02-20 2020-12-11 益阳市再超粉末冶金有限公司 一种用于汽车变速箱齿轮成型模具
KR102447825B1 (ko) * 2020-06-09 2022-09-27 세메스 주식회사 이종 복합물 및 상기 이종 복합물을 제조하는 방법
CN111975005B (zh) * 2020-08-26 2022-08-30 合肥工业大学 一种利用放电等离子体烧结技术一体化成型的钨铜穿管部件
CN115138840A (zh) * 2022-06-23 2022-10-04 上海兰石重工机械有限公司 一种粉末成型方法

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JPH0647336U (ja) * 1992-12-07 1994-06-28 日立粉末冶金株式会社 焼結滑り軸受
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JP2003222133A (ja) 2002-01-30 2003-08-08 Hitachi Powdered Metals Co Ltd 焼結含油滑り軸受
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WO2016052064A1 (fr) * 2014-09-30 2016-04-07 Ntn株式会社 Élément de coulissement et procédé pour sa fabrication
US10718379B2 (en) 2014-09-30 2020-07-21 Ntn Corporation Slide member and method for manufacturing same
US11619258B2 (en) * 2020-03-04 2023-04-04 Mahle International Gmbh Sliding bearing, method for producing a sliding bearing, internal combustion engine having a sliding bearing and electric machine having a sliding bearing
US20230227958A1 (en) * 2021-01-14 2023-07-20 Nsk Ltd. Method for carburizing steel member, steel component, and carburizing agent
US11732342B2 (en) * 2021-01-14 2023-08-22 Nsk Ltd Method for carburizing steel member, steel component, and carburizing agent

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EP3045241A1 (fr) 2016-07-20
CN105555445B (zh) 2018-10-30
EP3045241A4 (fr) 2017-05-10
US20160215820A1 (en) 2016-07-28
CN105555445A (zh) 2016-05-04

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